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gratter gieten geirrt @fitte Letters Patent No. 74,526, dated February 18, 1868.

GRATB-BARSQ @the ,Sittich nitriet tu in tinte @titers ittntt mth mating ritt mi itt stmt;

TO ALL Wl-IOM IT MAY CONCERN:

Be it known that I, ADDISON C. FLETCHER, of the city, county, and State of New York, have invented a new and useful ImprovementV in Grate-Bars; and I do hereby 4declare that the following is a full, clear, and exact description of the same, reference being had tothe accompanying drawings, forming part of this specification, in whichy I Figure 1v is a plan vof a portion of a grate composed of my improved bars,

Figure 2 isfa side view of. one of the bars.

Figure 8 is a transverse section of the same.

Figures 4, 5, and 6 are plan views illustrating modications of my invention.

Figure 7 is a transverse section of one ofthe bars represented in iig.

Similar letters of reference indicate corresponding parts in the several figures,

The object of this invention is threefold, viz, rst, to facilitate the circulation, and obtain a more uniform distribution of air among the fuel on the grate; second, to provide more eiiectually for the escape from the tirebed of the dust and ashes, which form vthe residue ofthe combustion of the fuel; and, third, to prevent the overheating of the bars.' To these ends the iuventionconsists in the construction of the upper part of the bars i with transverse recesses, which are of greater width toward or near the bottoms, forming a series of ducts,

through which theair may circulate under, and be distributed among the fuel, and, by the passage of the air through which, the upper parts of the bars are kept cool; audit further consists in the combination, with such transverse rccesses, of recesses in the sides of the bars, to facilitate the dropping from the fire ofthe dust and ashes.

To enable others to constrpct grate-bars according to my invention, I .will proceed to describe it with reference to the drawings. i

A A, gs..1, 2, 8, are the bars, the general form of which is the same as that of' ordinary grate-bars for furnaces, inasmuch as they are straight, with their thickness diminishing downward, as shown in the section, fig. 3, and they have cast on their sides projecting ribs a a and l b to keep their bodies at the required distance apart. The particulars in which they differ from ordinary bars are in their having recesses c c in their upper parts or faces, und recesses d el` in their sides communicating with the recesses c c. The recesses c c are at short intervals, so that the intervening portions e e of the upper part form a series of small stud-like bearings for the support of the fuel, under which. the air, admitted from'below the grate, and between the bars, can circu late in the recesses c @,insuchmanner as to provide for its more diffused circulation among ktho fuel. It will be seen, by referenceitoiig. 1, that' the recesscsc c have their width increased some distance below the faces or upper fuel-bearing surfaces of the bars, by which means not only is provision afforded for a more copious circu, lation of air, but for the cooling `of the fuel-bearing surfaces 4at the tops of the portions e e of the bars, and for the free falling away and riddance of the dust and ashes from the fuel. The recesses did are in the form of upright grooves in the sides of the bar communicating with the recesses o c, and are arranged in -opposite sides of the bar alternately, that is to say, that. in communication with'one recess, o, being on one side, and that in communication with thenext one being arranged on the other side of the bar, by which 'arrangement-the weaken ing of the bar is, in a great measure, ohviated, and a more uniform distribution of air to and amongthe fuel is obtained. These recesses dd not only provide for the free supply of air to the recesses c c, but for theV escape of the dust and ashes from them. In the modification shown in iig. 4, the recesses c c are so arranged as to form a series of round pins or stud-like projections, e e,'to constitute the fuel-bearing surfaces; and in fig; 5l the said recesses c c are so formed as to leave the intervening projections e e lozenge-shaped. In iigs. 6 and 7, the recesses c c extend obliquely across the bar, and their bottoms are bevelled in opposite directions, as shown in gji', at ff.v These modifications serve to illustrate my invention to make the recesses of various forms in their horizontal sections, all of which I consider equivalent to those illustrated in iig. 1i. I will remark that, in all cases, I intend to make the recesses wider or larger toward or near their bottoms, substantiallyas shown in iig. 2.

What I claim as my invention, and desire to secure by Letters Patent, isv

'.lhel alternating conical recesses d, in combination with the rounded points e, substantially asshown and described, for the purposes specified.

Witnesses:

J. W. CooMBs, G. W. REED.

ADDISON C. FLETCHER. 

